BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to systems and methods for protecting vehicle occupants
from injury. More specifically, the present invention relates to a deflection hood
that enhances the inflation profile of an airbag cushion.
2. Description of Related Art
[0002] The inclusion of inflatable safety restraint devices, or airbags, is now a legal
requirement for many new vehicles. Airbags are typically installed in the steering
wheel and in the dashboard on the passenger side of a car. Additionally, airbags may
be installed to inflate beside the passenger to provide side impact protection, in
front of the knees to protect the knees from impact, or at other strategic locations.
[0003] In the event of an accident, a sensor system within the vehicle senses an impact
situation and triggers the ignition of an inflator. Inflation gases from the inflator
fill the airbag cushions, which immediately inflate to protect the driver and/or passengers
from impact against the interior surfaces of the vehicle. During normal vehicle operation,
airbags are typically stowed behind covers to protect them from tampering and provide
a more attractive interior facade for the vehicle.
[0004] Often, airbags are designed to protect a vehicle occupant disposed at a certain projected
position. However, it has been noted that many vehicle occupants are out-of position
("OOP") at the time a collision occurs. Hence, airbags may advantageously be designed
to provide protection for an occupant disposed out of the typical impact position.
In the case of passenger side frontal impact airbags, a somewhat larger cushion may
be used to protect the passenger. The cushion may extend nearly from the roof to the
occupant's lap, and may also have a sizable lateral dimension to provide impact protection
in a variety of occupant positions.
[0005] Passenger side frontal impact airbags are often installed in the instrument panel
of the vehicle. Often, such airbags are installed on an upper surface of the instrument
panel. The inflator is installed within the panel and is disposed such that inflation
gas flows upward to cause the cushion to expand upward. Consequently, the cushion
tends to inflate toward the projected position of the occupant's head. The remainder
of the cushion may subsequently fill with inflation gas to cushion the occupant's
torso. However, such inflation may not be desirable because initial contact of only
the head with the cushion tends to put excessive strain on the neck. Furthermore,
such inflation may provide less protection for an out-of-position occupant.
[0006] Known solutions to this problem include the use of cushion tethers, special cushion
folding techniques, and internal devices such as loop diffusers. However, such solutions
typically have limitations. For example, tethers tend to limit depth of the cushion
toward the occupant, thereby reducing early restraint at the middle or rearward seat
positions. Special cushion folding techniques are often difficult and costly to perform.
Loop diffusers generally provide only limited improvement in deployment performance,
and are typically incapable of providing focused gas redirection.
[0007] US-A-5160164 discloses a gas deflection device in a passenger-side airbag module of the type having
an elongate inflator with multiple lateral gas discharge outlets and corresponding
to the preamble of claim 1. In one embodiment the detector comprises a single panel
extending across the width of the airbag cushion and secured to the inside of the
cushion on opposite sides. Gas from the inflator encounters the underside of the deflector
panel and is deflected downwards. In another embodiment the deflector extends only
part-way across the inside of the cushion and has a front edge constrained by tethers
to determine the direction of gas flow.
[0008] The apparatus of the present invention have been developed in response to the present
state of the art, and in particular, in response to the problems and needs in the
art that have not yet been fully solved by currently available airbag modules. Thus,
it is an overall objective of the present invention to provide an airbag module that
remedy the shortcomings of the prior art.
[0009] The present invention provides an airbag module for protecting an occupant of a vehicle
from impact, the airbag module comprising:
an inflator
a cushion disposable to receive inflation gas from the inflator along an inflation
direction; and
a deflection hood comprising an inlet portion attached to the cushion, the inlet portion
comprising an inlet opening disposed to receive inflation gas from the inflator along
the inflation direction, a top portion disposed to limit upward motion of the inflation
gas to redirect the inflation gas to a discharge direction angled at least forty-five
degrees downward from a horizontal plane, and an outlet portion comprising a discharge
opening disposed to release the inflation gas into the cushion along the discharge
direction, wherein the inlet portion, the top portion, and the outlet portion are
formed by first and second fabric sections integrally formed on opposite sides of
the inlet opening and having respective first and second outer edges attached to one
another to define the discharge opening.
[0010] The inflator may be seated in a housing, within which the cushion and deflection
hood are stowed. The inflator may be connected to an electronic control unit (ECU)
that is further coupled to a collision sensor, such as an accelerometer, so that the
ECU is able to transmit an activation signal to the inflator in response to detection
of a collision by the collision sensor. The vehicle has a windshield and an instrument
panel from which the cushion deploys.
[0011] In a typical embodiment the cushion has a first portion and a second portion; in
the inflated state, the first portion is disposed above the second portion, toward
the projected position of the occupants head. In the absence of the deflection hood,
the inflation gas tends to move into the first portion. The deflection hood has an
inlet portion adjacent to the inflator and housing within the instrument panel. The
deflection hood also has an outlet portion including forward and rearward regions,
and a top portion generally above the outlet portion.
[0012] A discharge opening is formed in the rearward region of the outlet portion and a
supplemental discharge opening may be formed in the forward region of the outlet portion.
The top portion of the deflection hood receives most of the inflation gas from the
inflator and deflects it downward and out of the deflection hood through the discharge
opening. Inflation gas exits the discharge opening along a discharge direction. The
discharge direction is angled downward from the horizontal plane by an angle of at
least forty-five degrees, such that the discharge direction is oriented generally
toward the second portion of the cushion.
[0013] The top portion also deflects a portion of the inflation gas downward, toward the
supplemental discharge opening. The portion of inflation gas exits the supplemental
discharge opening along a supplemental discharge direction to provide some venting
into the forward regions of the cushion. The deflection hood may also have vents on
either side to provide further lateral venting into the cushion.
[0014] The cushion may be formed with a first side, a second side, and a mounting portion
at which the cushion is attached to the housing. The mounting portion is thus disposed
adjacent to the instrument panel when the cushion inflates. First and second fabric
sections of the deflection hood, which are integrally formed with each other, are
preferably substantially symmetrical to each other along a lateral direction. The
first and second fabric sections have first and second side portions, respectively,
which inflate to positions generally parallel to the first and second sides of the
cushion.
[0015] The first and second fabric sections have first and second outer edges, respectively,
along which the first and second fabric sections are attached together by a method
such as sewing. The first and second fabric sections also have first and second discharge
edges and first and second supplemental discharge edges, respectively. The first and
second discharge edges and the first and second supplemental discharge edges are adjacent
to the first and second outer edges and are left unattached to provide the discharge
opening and the supplemental discharge opening.
[0016] In operation, the ECU transmits an activation signal to the inflator in response
to detection of a collision. The inflator releases inflation gas, which enters the
deflection hood through the inlet portion and flows into the top portion. The top
portion redirects the inflation gas into the outlet portion, which releases the inflation
gas via the discharge opening and the supplemental discharge opening. The inflation
gas exiting through the discharge opening moves toward the second portion of the cushion
to expedite inflation of the second portion, thereby providing enhanced cushioning
for occupants, especially out-of-position occupants.
[0017] Prior to assembly, the airbag module includes a hood panel that will become the deflection
hood and a cushion panel that will become the cushion. The airbag assembly also includes
a retainer ring and a plurality of nuts capable of engaging the retainer ring. The
hood panel has the first and second sections, the outer edges of which have not yet
been attached together to form the deflection hood.
[0018] The hood panel also has a central strip that connects the first and second fabric
sections together, the central strip is integrally formed with the first and second
fabric sections. An inlet opening is formed in the central strip to provide for inflation
gas entry into the deflection hood from the inflator. The central strip has a periphery
that surrounds the inlet opening. A plurality of attachment holes and alignment holes
are formed in the periphery to facilitate attachment of the deflection hood to the
cushion. The cushion has an inlet opening with a periphery having a similar arrangement
of attachment and alignment holes.
[0019] The retainer ring has a tubular wall and a flange that extends outward from one end
of the tubular wall. Fasteners are integrally formed with or attached to the flange
and extend toward the other components of the airbag module, in alignment with the
attachment holes of the cushion and the deflection hood. The fasteners may be bolts
or other threaded members, or the like. Additionally, tabs are formed in the flange
and extend toward the other components of the airbag module, in alignment with the
alignment holes.
[0020] The housing has side walls and a mounting plate in which an inlet opening is formed,
with a configuration similar to those of the hood panel and the cushion paneL The
mounting plate has a periphery surrounding the inlet opening, with attachment and
alignment holes formed in the periphery. The inflator has an exhaust portion that
vents inflation gas through a plurality of holes when the inflator deploys, and a
connection portion designed to be coupled to the ECU. The exhaust portion and the
connection portion are generally cylindrical in shape. A flange extends outward from
between the exhaust and connection portions. The flange has attachment holes aligned
with the attachment holes of the deflection hood, the cushion, and the housing, and
with the fasteners of the retainer ring.
[0021] The airbag module may be assembled by, first, attaching the cushion panel and the
hood panel together around the inlet openings of the cushion panel and the hood panel.
Then, the cushion panel and the hood panel are closed to form the cushion and the
deflection hood, respectively. According to one exemplary method, the edges of the
cushion panel are attached together to form the cushion. The first and second sections
of the hood panel are then drawn out of the cushion through the inlet openings of
the retainer ring, hood panel, and cushion. The outer edges of the first and second
sections are then attached together and the first and second sections are inserted
back through the inlet openings, into the cushion to form the deflection hood.
[0022] The retainer ring is then inserted through the inlet openings of the cushion and
the deflection hood. The fasteners are inserted through the attachment holes of the
cushion, the deflection hood, the housing, and the inflator. As the retainer ring,
deflection hood, cushion, housing, and inflator are brought together, the tabs enter
the alignment holes of the deflection hood, cushion, and housing. The exhaust portion
of the inflator passes through the inlet openings of the housing, cushion, deflection
hood, and retainer ring. The nuts are threaded onto the ends of the fasteners and
tightened to attach the retainer ring, deflection hood, cushion, housing, and inflator
together.
[0023] The cushion and the deflection hood may then be folded by simply compacting the cushion
and deflection hood into a stowed volume. No specific or ordered folding method need
be used; rather, the cushion and the deflection hood may simply be compressed into
the stowed volume. The deflection hood directs the inflation gases entering the cushion
so that the manner in which the cushion and deflection hood are folded plays a comparatively
small role in determining the inflation characteristics of the cushion.
[0024] The discharge edges and the supplemental discharge edges may be attached together
in a manner that permits the deflection hood to inflate prior to escape of the inflation
gas from the deflection hood. Sewn tear seams or the like may be used. When the inflation
gas within the deflection hood reaches a predetermined pressure differential, with
respect to the gas outside the deflection hood, the tear seams tear to open the discharge
opening and the supplemental discharge opening. Consequently, the discharge and supplemental
discharge openings are properly positioned prior to significant discharge of inflation
gas from the deflection hood.
[0025] The discharge edges and the supplemental discharge edges may be attached together
via non-frangible methods, such as sewing to form a non-tearable seam. For example,
the outer edges, the discharge edges, and the supplemental discharge edges may be
sewn with a continuous, uniform sewing process. In place of tearable seams, perforations
may be formed in the outlet portion, proximate the discharge and supplemental discharge
edges. When a predetermined pressure differential is reached, the outlet portion tears
along the perforations to open the discharge and supplemental discharge openings,
thereby releasing inflation gas.
[0026] The deflection hood may be oriented to provide asymmetrical discharge within the
cushion. For example, the attachment and alignment holes may be rotated about the
inlet opening of the deflection hood by an angle so that the deflection hood is angled
within the cushion. The discharge opening has an off-center location; hence, inflation
gas is discharged along an angle to provide asymmetrical lateral inflation.
[0027] Through the use of airbag modules of the present invention, airbags may inflate in
a manner that more effectively cushions the occupant against impact. Furthermore,
the airbag module may be efficiently and cost-effectively manufactured. These and
other features and advantages of the present invention will become more fully apparent
from the following description and appended claims, or may be learned by the practice
of the invention as set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order that the manner in which the other features and advantages of the invention
are obtained will be readily understood, a more particular description of the invention
briefly described above will be rendered by reference to specific embodiments thereof
which are illustrated in the appended drawings. Understanding that these drawings
depict only typical embodiments of the invention and are not therefore to be considered
to be limiting of its scope, the invention will be described and explained with additional
specificity and detail through the use of the accompanying drawings in which:
Figure 1 is a side elevation view of an airbag module according to the invention,
mounted as a passenger side, frontal impact airbag within the instrument panel of
a vehicle;
Figure 2 is a partially cut away perspective view of the cushion and the deflection
hood of the airbag module of Figure 1, during inflation;
Figure 3 is an exploded, perspective view of the airbag module of Figure 1 in a partially
assembled state, with only a portion of the cushion shown;
Figure 4 is a perspective view of a deflection hood suitable for use in the cushion
of the airbag module of Figure 1, according to one alternative embodiment of the invention;
Figure 5 is a perspective view of a deflection hood suitable for use in the cushion
of the airbag module of Figure 1, according to another alternative embodiment of the
invention; and
Figure 6 is a plan view of a hood panel used to form a deflection hood according to
another alternative embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] The presently preferred embodiments of the present invention will be best understood
by reference to the drawings, wherein like parts are designated by like numerals throughout.
It will be readily understood that the components of the present invention, as generally
described and illustrated in the figures herein, could be arranged and designed in
a wide variety of different configurations. Thus, the following more detailed description
of the embodiments of the apparatus of the present invention, as represented in Figures
1 through 6, is not intended to limit the scope of the invention, as claimed, but
is merely representative of presently preferred embodiments of the invention.
[0030] For this application, the phrases "connected to," "coupled to," and "in communication
with" refer to any form of interaction between two or more entities, including mechanical,
electrical, magnetic, electromagnetic, and thermal interaction. The phrase "attached
to" refers to a form of mechanical coupling that restricts relative translation or
rotation between the attached objects. The phrases pivotally attached to" and "slidably
attached to" refer to forms of mechanical coupling that permit relative rotation or
relative translation, respectively, while restricting other relative motion.
[0031] The phrase "attached directly to" refers to a form of attachment by which the attached
items are either in direct contact, or are only separated by a single fastener, adhesive,
or other attachment mechanism. The term "abutting" refers to items that are in direct
physical contact with each other, although the items may not be attached together.
The term "grip" refers to items that are in direct physical contact with each other,
wherein one item holds the other firmly. The term "overlap" refers to items that are
proximate to each other, wherein one extends over and covers a part of the other,
but not necessarily in contact with each other.
[0032] Referring to Figure 1, a side elevation view shows an airbag module 10 according
to one embodiment of the invention. The airbag module 10 is designed to provide passenger's
side, frontal impact protection. However, those of skill in the art will recognize
that the present invention is equally applicable to other types of airbags, such as
knee bolsters, overhead airbags, inflatable curtains, inflatable structural stiffeners,
and the like.
[0033] The vehicle 12 has a longitudinal direction 14, a lateral direction 16, and a transverse
direction 18. As illustrated, the vehicle 12 has a seat 20 in which an occupant 22
is seated. The occupant 22 has a head 24, a torso 26, and a lap 28. A seat belt 30
provides primary restraint for the occupant 22. The vehicle 12 also has a front door
32 beside the occupant 22, a windshield 34 forward of the occupant 22, and an instrument
panel 36 disposed generally underneath the windshield 24. The airbag module 10 is
stowed within an upper surface 38 of the instrument panel 36 so that the airbag module
10 emerges generally upward from the upper surface 38.
[0034] As shown, the airbag module 10 has a cushion 40, which is illustrated in fully inflated
form. The airbag module 10 also has an inflator 42 seated within the instrument panel
36 to provide inflation gas to the cushion 40. The inflator 42 may be of any known
type, including compressed gas, pyrotechnic, and hybrid inflators. The airbag module
10 also has a deflection hood 44 disposed within the cushion 44 to direct the flow
of inflation gas into the cushion 40 in a manner that will be more fully set forth
hereafter.
[0035] The airbag module 10 also has a housing 46 disposed within the instrument panel 36.
The housing 46 may be affixed to the interior framework of the instrument panel 36.
The inflator 42 is secured to the housing 46 and the cushion 40 and the deflection
hood 44 are stowed, prior to deployment, in a stowed volume 48 defined by the housing
46. The stowed volume 48 is outside the inflator 42 so that inflation gas from the
inflator 42 must flow into the deflection hood 44 and/or the cushion 40 in order to
exit the housing 46.
[0036] An electronic control unit 50, or ECU 50, is disposed within the vehicle 12. The
ECU 50 need not be located as shown, but may be disposed at a variety of locations
within the vehicle 12. The ECU 50 is coupled to the inflator 42 via wires 52. A collision
sensor such as an accelerometer 54 or the like is coupled to the ECU 50 via wires
56. The accelerometer 54 transmits a signal to the ECU 50 to indicate that a collision
is occurring or is about to occur. The ECU 50 then transmits an activation signal
to the inflator 42 to trigger deployment of the inflator 42. The inflator 42 then
releases inflation gas to inflate the cushion 40.
[0037] The cushion 40 has a first portion 60 that, in the embodiment of Figure 1, is upwardly
disposed when the cushion 40 is inflated. Similarly, the cushion 40 has a second portion
62 disposed toward the lap 28 of the occupant 22, beneath the first portion 60. According
to some traditional airbag module designs, the upper portion of the cushion would
inflate first to contact the head 24 of the occupant 22, thereby placing excessive
strain on the neck. In the airbag module 10, the deflection hood 44 acts to direct
inflation gas into the second portion 62 to spread impact with the cushion 40 over
a larger portion of the body of the occupant 22.
[0038] The deflection hood 44 has an inlet portion 64 adjoining the housing 46 to receive
inflation gas from the inflator 42. An outlet portion 66 is disposed generally forward
and rearward of the inlet portion 64 to release the inflation gas into the cushion
40. A top portion 68 lies alongside the windshield 34 during inflation and is disposed
above the inlet and outlet portions 64, 66. The top portion 68 may comprise the majority
of the deflection hood 44, while the inlet portion 64 and the outlet portion 66 are
comparatively narrow regions disposed at the periphery of the deflection hood 44.
[0039] The inlet portion 64 has a discharge opening 70 disposed generally rearward of the
inlet portion 64. Additionally, the inlet portion 64 has a supplemental discharge
opening 72 forward of the inlet portion 64. The discharge opening 70 is considerably
larger than the supplemental discharge opening 72, and thus releases the majority
of the inflation gas. Vents 74 may optionally be provided in the sides of the top
portion 68 of the deflection hood 44 to release inflation gas laterally, thereby expediting
inflation of the cushion 40 in the lateral direction 16.
[0040] As shown, the discharge opening 70 releases inflation gas into the cushion 40 along
a discharge direction 76. The discharge direction 76 is oriented generally toward
the second portion 62 of the cushion 40, and is thus angled downward from a horizontal
plane 78 by an angle 80. The angle 80 may range from about 0° to about 145°. More
precisely, the angle 80 may range from about 30° to about 90°. Yet more precisely,
the angle 80 may range from about 45° to about 85°. Further, the angle 80 may range
from about 60° to about 80°. Yet further, the angle 80 may range from about 65° to
about 75°, and may be about 70°.
[0041] The inflation gas enters the deflection hood 44 along an inflation direction 82,
which may be generally upward. The top portion 68 is rounded in such a manner that
a substantial portion of the inflation gas is captured and redirected along a redirection
path 84, as illustrated in Figure 1. The top portion 68 has a generally domed shape.
Hence, the redirection path 84 has a comparatively continuous curvature that facilitates
stable flow through the deflection hood 44. The redirection path 84 alters the flow
orientation of the inflation gas from the inflation direction 82 to the discharge
direction 76. In this application, "generally domed" refers to a shape with a continuous,
but possibly variable radius three-dimensional curvature that provides an outward
bow. A "generally domed" shape need not be a section of a sphere, but may have a more
complex shape.
[0042] A portion of the inflation gas exits the supplemental discharge opening 72 along
a supplemental discharge direction 86, which extends forward to fill forward portions
of the cushion 40. The supplemental discharge opening 72 and the vents 74 may be somewhat
smaller than the discharge opening 70 so that the majority of the inflation gas is
directed out through the discharge opening 70 and toward the second portion 62 of
the cushion 40. The supplemental discharge opening 72 and the vents 74 are optional.
[0043] Referring to Figure 2, a cutaway, perspective view further illustrates the cushion
40 and the deflection hood 44 of Figure 1, during inflation As shown, the cushion
40 has a first side 90 and a second side 92, which are oriented generally vertically,
within parallel planes defined by the longitudinal and transverse directions 14, 18.
The cushion 40 also has a mounting portion 94 disposed to lie generally along the
upper surface 38 (not shown in Figure 2) of the instrument panel 36. The inlet portion
64 of the deflection hood 44 is attached to the mounting portion 94, and the mounting
portion 94 is attached to the housing 46 in a manner that will be set forth in greater
detail subsequently. The cushion 40 may include vents, tethers, or other features
known in the art.
[0044] The deflection hood 44 has a first fabric section 100 and a second fabric section
102, which are integrally formed with each other (
i.e., formed of a single continuous expanse of fabric). The first fabric section 100 extends
adjacent and parallel to the first side 90 of the cushion 40 to define a first side
portion 104 of the deflection hood 44. Similarly, the second fabric section 102 extends
adjacent and parallel to the second side 92 of the cushion 40 to define a second side
portion 106 of the deflection hood 44. The first and second side portions 104, 106
and the first and second sides 90, 92 may be somewhat curved during inflation, but
are still "generally parallel" to each other. Hence, "generally parallel" members
need not be flat or precisely parallel.
[0045] The first fabric section 100 of the deflection hood 44 has a first outer edge 108,
and the second fabric section 102 has a second outer edge 110. The outer edges 108,
110 extend between the discharge opening 70 and the supplemental discharge opening
72. The outer edges 108, 110 are attached together via a method such as sewing, adhesive
bonding, chemical bonding, radio frequency (RF) welding, ultrasonic welding, one-piece
weaving (OPW), application of rigid mechanical fasteners, or the like. In the embodiment
of Figure 2, the first and second fabric sections 100, 102 are sewn together to form
a seam 111 that attaches the first fabric section 100 to the second fabric section
102.
[0046] The first and second fabric sections 100, 102 also have first and second discharge
edges 112, 114, respectively, which are disposed adjacent to the first and second
outer edges 108, 110, respectively. The first and second discharge edges 112, 114
cooperate to define the discharge opening 70. In the embodiment of Figure 2, the first
and second discharge edges 112, 114 are not attached to each other so that inflation
gas is able to flow freely from the discharge opening 70 at the commencement of inflation.
[0047] Similarly, the first and second fabric sections 100, 102 have first and second supplemental
discharge edges 116, 118, respectively, which are also disposed adjacent to the first
and second outer edges 108, 110. The first outer edge 108 is between the first discharge
edge 112 and the first supplemental discharge edge 116, and the second outer edge
110 is between the second discharge edge 114 and the second supplemental discharge
edge 118. The first and second supplemental discharge edges 116, 118 also cooperate
to define the supplemental discharge opening 72, which is open to release inflation
gas at the commencement of inflation.
[0048] As shown, the visible vent 74 of the deflection hood 44 releases inflation gas along
a venting direction 120, which extends, at least in part, along the lateral direction
16. The opposite vent 74 (not visible in Figure 2) releases inflation gas along a
venting direction with a lateral component generally opposite to that of the illustrated
venting direction 120. The vents 74 expedite inflation of the lateral extents of the
cushion 40, which may enhance protection if the occupant 22 is leaning to one side
or the other.
[0049] The various elements of the airbag module 10 may be manufactured and assembled according
to a wide variety of methods. One such method will be shown and described in connection
with Figure 3, as follows.
[0050] Referring to Figure 3, a perspective view illustrates an airbag module 122 in an
exploded, unassembled state. When assembly is completed, the airbag module 122 will
be the airbag module 10 of Figures 1 and 2. As shown, the airbag module 122 includes
a hood panel 124 that will become the deflection hood 44 and a cushion panel 126 that
will become the cushion 40. To avoid obscuring other aspects of the airbag module
122, only the mounting portion 94 of the cushion panel 126 is shown in Figure 3. The
airbag module 122 also has a retainer ring 130 that may be used in conjunction with
a plurality of nuts 132 to attach the hood panel 124, the cushion panel 126, the housing
46, and the inflator 42 together.
[0051] As illustrated, the first and second fabric sections 100, 102 are formed in the hood
panel 124 and are connected together via a central strip 136. The first and second
fabric sections are integrally formed in the central strip 136, for example, by laser
cutting an expanse of fabric in the shape of the hood panel 124. An inlet opening
138 is formed in the central strip 136, midway between the first and second fabric
sections 100, 102. The central strip 136 has a periphery 140 surrounding the inlet
opening 138.
[0052] A plurality of attachment holes 142 are arranged in radially symmetrical fashion
about the periphery 140. A plurality of alignment holes 144 are also arranged about
the periphery 140. In the embodiment of Figure 3, four attachment holes 142 are present,
and two alignment holes 144 are disposed between each adjacent pair of attachment
holes 142.
[0053] The cushion panel 126 may also be formed by laser cutting the shape of the cushion
panel 126 from a single expanse of fabric. Alternatively, multiple fabric pieces may
be attached together to form the cushion panel 126. The cushion panel 126 may have
any of a wide variety of shapes known in the art. The mounting portion 94 of the cushion
panel 126 has a similarly disposed inlet opening 138 surrounded by a periphery 140.
Attachment holes 142 and alignment holes 144 are arranged about the periphery 140
of the mounting portion 94, in alignment with the attachment holes 142 and alignment
holes 144 of the central strip 136 of the hood panel 124.
[0054] The retainer ring 130 may be formed of a metal such as steel or aluminum, or may
optionally be formed of a plastic, ceramic, or composite. In the embodiment of Figure
3, the retainer ring 130 has a tubular wall 146 that encircles an inlet opening 138
similar in size to the inlet opening 138 of the hood panel 124 and the inlet opening
138 of the cushion panel 126. The retainer ring 130 also has a flange 150 that extends
outward, in the longitudinal and lateral directions 14, 16, from the tubular wall
146.
[0055] A plurality of fasteners 152 are attached to or formed integrally with the flange
150, in alignment with the attachment holes 142 of the hood panel 124 and the cushion
panel 126. The fasteners 152 extend toward the hood panel 124. Each of the fasteners
152 may be a bolt, a threaded stud, or the like. In the embodiment of Figure 3, four
fasteners 152 are provided to correspond to the number of attachment holes 142 present
in the peripheries 140 of the hood panel 124 and the cushion panel 126. Additionally,
eight tabs 154 are formed in the flange 150, for example, via punching. The tabs 154
correspond to and are aligned with the alignment holes 144 of the peripheries 140
of the hood panel 124 and the cushion panel 126.
[0056] The housing 46 has side walls 156 that define a generally rectangular-prismoidal
shape, and a mounting plate 158 disposed generally perpendicular to the side walls
156. The mounting plate 158 has an inlet opening 138 similar in size to the inlet
openings 138 of the retainer ring 130, the hood panel 124, and the cushion panel 126.
The mounting plate 158 has four attachment holes 142 and eight alignment holes 144
arranged about the inlet opening 138 of the mounting plate 158. The attachment holes
142 and alignment holes 144 of the mounting plate 158 are aligned with the attachment
holes 142 and alignment holes 144, respectively, of the hood panel 124 and the cushion
panel, and aligned with the fasteners 152 and tabs 154, respectively, of the retainer
ring 130.
[0057] The inflator 42 may have a generally cylindrical shape with an exhaust portion 160
designed to release inflation gas and a connection portion 162 designed to be coupled
to the ECU 50 (not shown in Figure 3). The exhaust portion 160 is separated from the
connection portion 162 by a flange 164 that extends generally along the longitudinal
and lateral directions 14, 16. A plurality of attachment holes 142 are formed in the
flange 164, in alignment with the attachment holes 142 of the hood panel 124, the
cushion panel 126, and the housing 46, and with the fasteners 152 of the retainer
ring 130.
[0058] A plurality of holes 166 may be formed in the exhaust portion 160 of the inflator
42 to release inflation gas from the interior of the inflator 42 when the inflator
42 deploys. The holes 166 are oriented to release generally radial outflows of inflation
gas from the inflator 42, thereby providing substantially thrust-neutral deployment.
The wires 52 that couple the inflator 42 to the ECU 50 may have connectors 170 designed
to fit into receptacles (not shown) in the connection portion 162 of the inflator
42.
[0059] The airbag module 122 may be easily assembled to form the airbag module 10 illustrated
in Figures 1 and 2. According to one method, the hood panel 124 may first be attached
to the cushion panel 126. Stitching (not shown) may be applied along the peripheries
140 around the inlet openings 138 of the hood panel 124 and the cushion panel 126
to attach the hood panel 124 to the cushion panel 126.
[0060] Before the retainer ring 130, the housing 46, and the inflator 42 are attached, the
hood panel 124 and the cushion panel 126 may be closed to form the deflection hood
44 and the cushion 40, respectively. More precisely, the cushion panel 126 may first
be closed by sewing edges (not shown) of the cushion panel 126 together. This may
be performed by sewing or other methods known in the art. In this application, "close"
does not necessarily refer to complete or airtight enclosure of a space.
[0061] If desired, the edges of the cushion panel 126 may be drawn through the inlet openings
138 of the hood panel 124 and the cushion panel 126 prior to attachment, and then
inserted back through the inlet openings 138 after attachment, so that upon completion
of the process, the edges roll inward toward each other and are attached at internal
seams. Such a configuration may provide greater seam strength. In any case, the cushion
40 then encloses the hood panel 124, which has not yet been closed to form the deflection
hood 44.
[0062] In order to close the hood panel 124, the first and second fabric sections 100, 102
may first be withdrawn at least partially through the inlet openings 138 of the cushion
40 and the hood panel 124, so that the first and second outer edges 108, 110 are accessible
from outside the cushion 40. The first and second outer edges 108, 110 may then be
sewn together to form the seam 111. As mentioned previously, the first and second
discharge edges 112, 114 and the first and second supplemental discharge edges 116,
118 remain unattached to define the discharge opening 70 and the supplemental discharge
opening 72.
[0063] After the first and second outer edges 108, 110 have been attached together, the
first and second fabric sections 100, 102 may be inserted back through the inlet openings
138 of the cushion 40 and the deflection hood 44. Thus, the deflection hood 44 is
turned right-side-out and disposed within the cushion 40. The first and second edges
100, 102 are bent inward, toward each other and the seam 111 is disposed within the
deflection hood 44.
[0064] After the hood panel 124 and the cushion panel 126 have been closed to form the cushion
40 and the deflection hood 44, the retainer ring 130 may be inserted through the inlet
openings 138 of the cushion 40 and the hood 44. The retainer ring 130 may then be
inserted into engagement, along the transverse direction 18, with the deflection hood
44 and the cushion 40 such that the fasteners 152 extend through the attachment holes
142 and the tabs 154 extend through the alignment holes 144 of the deflection hood
44 and the cushion 40.
[0065] The housing 46 and the inflator 42 may be inserted into engagement with the retainer
ring 130 along the transverse direction 18. The fasteners 152 then extend through
the attachment holes 142 of the hood panel 124, the cushion panel 126, the housing
46, and the inflator 42, and the tabs 154 extend through the alignment holes 144 of
the hood panel 124, the cushion panel 126, and the housing 46. The nuts 132 are threaded
into engagement with the exposed ends of the fasteners 152 to secure the engagement
of the retainer ring 130 with the hood panel 124, the cushion panel 126, the housing
46, and the inflator 42.
[0066] The exhaust portion 160 of the inflator 42 then extends through the inlet openings
138 of the housing 46, the cushion 40, the deflection hood 44, and the retainer ring
130. Thus, the exhaust portion 160 is disposed in the interior of the deflection hood
44, within the space defined by the tubular wall 146 of the retainer ring 130. The
tubular wall 146 may cover some of the holes 166 of the exhaust portion 160 of the
inflator 42 to control the directions along which inflation gas is able to exit the
exhaust portion 160. As long as the holes 166 are covered in symmetrical fashion,
thrust neutrality of the inflator 42 may be maintained.
[0067] The cushion 40 and the deflection hood 44 may then be folded into the housing 46.
Folding may be accomplished through the use of automated machinery and/or manual labor.
According to one embodiment, the cushion 40 and the deflection hood 44 are not folded
according to a pre-established pattern, but are rather simply compacted into the stowed
volume 48 within the interior of the housing 46. The term "folding" is used loosely
to include both ordered and randomized fabric compaction techniques.
[0068] Such randomized folding may be termed "chaos folding," and may enhance the cost-effectiveness
of the airbag module 10 by eliminating machinery and process steps required to carry
out complex folding methods. Such folding methods are often used in airbag modules
to control the inflation path of the cushion. However, the deflection hood 44 of the
airbag module 10 may provide such control, even when the compaction of the cushion
40 and the deflection hood 44 is somewhat randomized.
[0069] According to alternative embodiments, the cushion 40 and the deflection hood 44 may
be folded according to more ordered methods. Such folding may, if desired, be carried
out prior to attachment of the housing 46 and the inflator 42 to the retainer ring
130. The folded package including the cushion 40 and the deflection hood 44 may then
be coupled to the housing 46 and the inflator 42. Alternatively, ordered folding may
be carried out after the housing 46 and/or the inflator 42 have been positioned with
respect to the retainer ring 130.
[0070] After the cushion 40 and the deflection hood 44 have been folded into the shape of
the stowed volume 48, the airbag module 10 is ready to be installed in the vehicle
12. The wires 52 may be attached to the connection portion 162 of the inflator 42
via the connectors 170. The housing 46 may be attached to the interior of the instrument
panel 36 in a variety of ways.
[0071] When a collision is detected, the ECU 50 transmits an activation signal to the inflator
42 via the wires 52. The inflator 42 receives the activation signal and deploys to
release inflation gas from the holes 166 of the exhaust portion 160 of the inflator
42. The inflation gas generally impinges against the top portion 68 of the deflection
hood 44 to inflate the deflection hood 44 within the cushion 40. A portion of the
inflation gas moves along the redirection path 84 and exits the deflection hood 44
via the discharge opening 70. Other portions of the inflation gas exit the deflection
hood 44 via the supplemental discharge opening 72 and the vents 74, as illustrated
in Figure 2.
[0072] During deployment, the top portion 68 of the deflection hood 44 lies alongside the
windshield 34, as shown in Figure 1. The pressure of inflation gas within the top
portion 68 maintains the shape of the deflection hood 44 despite the reaction pressure
exerted on the top portion 68 by the windshield 34. Hence, the deflection hood 44
maintains a consistent general shape during inflation.
[0073] The windshield 34 prevents forward motion of the top portion 68. Consequently, the
deflection hood 44 is unable to pivot forward in response to the thrust exerted by
inflation gas exiting the discharge opening 70. The discharge opening 70 remains in
place to discharge inflation gas along the discharge direction 76, as desired. The
top portion 68 may be re-shaped in a variety of ways to suit different vehicle configurations
and windshield shapes.
[0074] The inflation gas is thus directed into the second portion 62 of the cushion 40 to
ensure that the second portion 62 inflates rapidly enough to provide relatively uniform
impact protection for the head 24 and torso 26 of the occupant 22. The cushion 40
may have vents or gas-permeable membranes designed to release gas from the cushion
40 during inflation at a limited flow rate to limit the stiffness of the cushion 40
during inflation.
[0075] In alternative embodiments of the invention, it may be desirable to limit the initial
flow of inflation gas from the deflection hood 44 to ensure that the deflection hood
44 inflates properly prior to release of most of the inflation gas into the cushion.
This would ensure that the discharge opening 70 rapidly obtains the proper position
to release the inflation gas along the discharge direction 76. Furthermore, in alternative
embodiments, it may be desirable to implement measures to ensure that the hood panel
124 cannot be closed in a twisted position. Such alternative embodiments will be shown
and described in connection with Figures 4 and 5, as follows.
[0076] Referring to Figure 4, a perspective view illustrates a deflection hood 244 according
to one alternative embodiment of the invention. The deflection hood 244 may be used
in place of the deflection hood 44, in conjunction with the remaining components of
the airbag module 10, or with components configured differently from those of the
previous embodiment. The deflection hood 244 is shown during the initial stages of
inflation.
[0077] Like the previous embodiment, the deflection hood 244 has an inlet portion 64 through
which inflation gas enters the deflection hood 244 and a top portion 68 that redirects
the inflation gas. The deflection hood 244 also has an outlet portion 266, which is
configured somewhat differently from that of the previous embodiment, as will be described
below. The outlet portion has a discharge opening 270 and a supplemental discharge
opening 272 that release inflation gas into a cushion (not shown).
[0078] The deflection hood 244 also has a first fabric section 300 and a second fabric section
302. The first fabric section 300 has a first side portion 304, and the second fabric
section has a second side portion 306, which are different from the side portions
104, 106 of the previous embodiment in that the vents 74 have been omitted. The first
and second fabric sections 300, 302 have first and second outer edges 108, 110, respectively,
like those of the previous embodiment, which are attached together via a seam 111.
[0079] The first and second fabric sections 300, 302 also have first and second discharge
edges 312, 314, respectively, which cooperate to define the discharge opening 270.
The first and second discharge edges 312, 314 are different from those of the previous
embodiment in that they are attached together via a seam 315. The seam 315 has a strength
selected such that, when a predetermined pressure differential exists between the
interior and exterior of the deflection hood 244, the seam 315 tears to permit inflation
gas to exit the deflection hood 244 via the discharge opening 270.
[0080] Similarly, the first and second fabric sections 300, 302 have first and second supplemental
discharge edges 316, 318, respectively, which cooperate to define the supplemental
discharge opening 272. The first and second supplemental discharge edges 316, 318
are attached together via a seam 319 with a strength selected to permit the seam 319
to tear in response to formation of the predetermined pressure differential to release
inflation gas through the supplemental discharge opening 272.
[0081] Use of the seams 315, 319 helps to ensure that the deflection hood 244 substantially
fills with inflation gas prior to significant gas release into the cushion. Thus,
the discharge opening 270 and the supplemental discharge opening 272 will be properly
positioned when they open to release inflation gas. Hence, the inflation gas will
initially flow along the desired directions (such as the discharge and supplemental
discharge directions 76, 86 of Figure 1), rather than exiting the deflection hood
244 at unpredictable orientations until gas flow through the deflection hood 244 stabilizes.
[0082] The seams 315, 319 may be manufactured according to a number of different methods.
According to one method, the airbag module including the deflection hood 244 may be
assembled as described in connection with the previous embodiment, up to the point
at which the deflection hood 44 is closed. Rather than simply sewing the outer edges
108, 110 of the deflection hood 244, the discharge and supplemental discharge edges
312, 314 and 316, 318 are also attached together.
[0083] Optionally, the discharge and supplemental discharge edges 312, 314 and 316, 318
may be attached together via continuation of the process used to attach the outer
edges 108, 110. One or more parameters of the sewing operation, such as the thread
type, stitch spacing, or the like may simply be altered to form the seams 315, 319
in a way that provides a tear strength lower than that of the seam 111. Alternatively,
the seams 315, 319 may be sewn through an operation separate from that used to form
the seam 111. Once the seams 111, 315, 319 have all been formed, the deflection hood
244 is inserted back into the cushion and disposed right-side out, as described in
connection with the previous embodiment
[0084] Tearable attachment of the discharge and supplemental discharge edges 312, 314, 316,
318 has the added advantage of helping to prevent improper closure and installation
of the deflection hood 244. More precisely, after the discharge and supplemental discharge
openings 270, 272 have been sewn shut, the first and second fabric sections 300, 302
cannot be twisted into the wrong stable position by accidental insertion through the
discharge opening 270 or the supplemental discharge opening 272.
[0085] Furthermore, improper attachment of the first and second fabric sections 300, 302
may be more immediately noticeable and/or correctable because the discharge edges
312, 314 are shaped and sized differently from the supplemental discharge edges 316,
318. Thus, attachment of one of the discharge edges 312, 314 to one of the supplemental
discharge edges 316, 318 will be more immediately obvious.
[0086] Referring to Figure 5, a perspective view illustrates a deflection hood 344 according
to another alternative embodiment of the invention. The deflection hood 344 may be
used in place of the deflection hood 44, in conjunction with the remaining components
of the airbag module 10, or with components configured differently from those of the
first embodiment. The deflection hood 244 is shown during the initial stages of inflation.
[0087] Like the previous embodiments, the deflection hood 344 has an inlet portion 64 that
receives inflation gas and a top portion 68 that redirects the inflation gas. The
deflection hood 344 also has an outlet portion 366 through which inflation gas is
released into a cushion (not shown). The outlet portion 366 has a discharge opening
370 and a supplemental discharge opening 372.
[0088] The deflection hood 344 has a first fabric section 400 and a second fabric section
402. The first fabric section 400 has a first side portion 304 like that of the previous
embodiment. Similarly, the second fabric section 402 has a second side portion 306.
The first and second fabric portions 400, 402 have first and second outer edges 108,
110, respectively, which are also like those of the previous embodiment. The first
and second outer edges 108, 110 are attached via a seam 111.
[0089] The first and second fabric sections 400, 402 have first and second discharge edges
412, 414, respectively, which cooperate to define the discharge opening 370. The first
and second discharge edges 412, 414 are attached together via a seam 415 that is generally
non-tearable in nature. The first and second fabric sections 400, 402 also have first
and second supplemental discharge edges 416, 418, respectively, which cooperate to
define the supplemental discharge opening 372. The first and second supplemental discharge
edges 416, 418 are attached together via a seam 419 that is also non-tearable.
[0090] The outlet portion 366 has a perforated region 422 formed in the second fabric section
402, proximate the second discharge edge 414. The perforated region 422 has a plurality
of perforations 424 arranged in a line along the second discharge edge 414. The perforations
424 are spaced apart such that the perforated region 422 has a low tear strength along
the perforations 424. The perforated region 422 may thus tear open to provide the
discharge opening 370 when a predetermined pressure differential is reached between
the interior and exterior of the deflection hood 344.
[0091] Similarly, the outlet portion 366 has a perforated region 426 formed in the second
fabric section 402, proximate the second supplemental discharge edge 418. The perforated
region 426 has a plurality of perforations 428 arranged in a line along the second
supplemental discharge edge 418. Like the perforations 424, the perforations 428 are
spaced apart such that the perforated region 428 has a low tear strength along the
perforations. Consequently, the perforated region 426 may tear open to provide the
supplemental discharge opening when the predetermined pressure differential is reached.
[0092] Hence, the deflection hood 344 provides benefits comparable to those of the previous
embodiment. The discharge opening 370 and the supplemental discharge opening 372 are
generally disposed in their proper positions prior to significant inflation gas release
into the cushion. Furthermore, improper closure or installation of the deflection
hood 344 is difficult and/or comparatively easy to notice.
[0093] The seams 415, 419 may be easily manufactured through methods like those used to
form the seam 111. Since the seams 415, 419 are substantially non-tearable, like the
seam 111, the seams 111, 415, 419 may be formed through the use of one continuous
sewing operation, with no required parameter changes. Thus, the outer edges 108, 110,
the discharge edges 412, 414, and the supplemental discharge edges 416, 418 may be
attached continuously together so that the seams 111, 415, 419 are effectively one
continuous seam.
[0094] The perforations 424, 428 may be formed in a variety of ways. According to one example,
the perforations 424, 428 are formed via laser cutting. The perforations 424, 428
may thus be formed as part of a laser cutting process used to form the outer edges
108 110, the discharge edges 412, 414, and the supplemental discharge edges 416, 418
to define the shape of the cushion panel that forms the deflection hood 344.
[0095] In certain implementations, it may be desirable to deflect gas in a direction with
a lateral component to provide preferential inflation on one side of a deflection
hood. Such asymmetrical inflation may be used to compensate for curvature in a windshield
or instrument panel, or to enhance out-of-position impact protection. One example
of a hood panel designed to provide such laterally asymmetrical inflation gas flow
will be shown and described in connection with Figure 6.
[0096] Referring to Figure 6, a plan view illustrates a hood panel 524 that may be used
to manufacture a deflection hood according to yet another alternative embodiment of
the invention. The resulting deflection hood may be used in place of the deflection
hood 44, in conjunction with the remaining components of the airbag module 10, or
with components configured differently from those of the first embodiment to provide
lateral component to inflation gas release into the cushion (not shown).
[0097] Like the hood panel 124, the hood panel 524 has a first fabric section 100, a second
fabric section 102, and a central strip 536 that couples the first and second fabric
sections 100, 102 together. The first and second fabric sections 100, 102 have first
and second side portions 104, 106, respectively. Furthermore, the first fabric section
100 has a first outer edge 108, a first discharge edge 112, and a first supplemental
discharge edge 116. The second fabric section 102 has a second outer edge 110, a second
discharge edge 114, and a second supplemental discharge edge 118.
[0098] The central strip 536 has an inlet opening 138 through which inflation gas is able
to enter the deflection hood made from the hood panel 124. A periphery 540 surrounds
the inlet opening 138. A plurality of attachment holes 142 and alignment holes 144
are distributed about the periphery 540. The attachment holes 142 and alignment holes
144 are similar to those of the embodiment of Figure 3, and may be used to receive
fasteners and tabs like the fasteners 152 and tabs 154 of the retainer ring 130 of
Figure 3.
[0099] The periphery 540 is different from the periphery 140 of the hood panel 124 of Figure
3 in that, in the periphery 540, the attachment holes 142 and alignment holes 144
are rotated from their positions in the periphery 140 by an angle 542. The angle 542
is selected to provide the lateral component to inflation gas release. A larger angle
542 provides increased lateral flow and greater asymmetry. As shown, the angle 542
is about twenty degrees in the embodiment of Figure 6.
[0100] The effect of the angle 542 is that the hood panel 524 may be used in place of the
hood panel 124 to provide an airbag module similar in configuration to the airbag
module 10 of Figures 1 and 2. However, the deflection hood (not shown) produced by
closure of the hood panel 524 would be angled such that the discharge opening is directed
inboard and the supplemental discharge opening is directed outboard. The result is
that most of the inflation gas is directed inboard (e.g., along the leftward lateral
direction 16, with respect to the view of Figure 6) as well as downward.
[0101] The lateral discharge component may help to compensate for an instrument panel (not
shown) with a curvature that extends toward the vehicle occupants in the middle of
the vehicle, and recedes at the ends. Such an instrument panel shape may ordinarily
cause the passenger side cushion to inflate outboard. This effect may be at least
partially negated by the existence of the angle 542. According to other alternative
embodiments, an opposite angle may be used to provide outboard inflation gas flow
to compensate for a windshield that curves away from the vehicle occupants in the
center.
[0102] The present invention may be embodied in other specific forms without departing from
its structures, methods, or other essential characteristics as broadly described herein
and claimed hereinafter. The described embodiments are to be considered in all respects
only as illustrative, and not restrictive. The scope of the invention is, therefore,
indicated by the appended claims, rather than by the foregoing description. All changes
that come within the meaning and range of equivalency of the claims are to be embraced
within their scope.